Static IP is a manual way of configuring an IP address, gateway, network mask and name server (DNS) for your computer. The IP address is predetermined and always the same (a must if you are running internet services like a web or FTP server on a client). Configuring with a static IP is more work, prone to errors, and can lead to so called IP address conflicts if you do not keep track of all the IP addresses in your network.

The main benefit of dynamic over static on workstations is that it makes management much easier. If you need to make network changes, you can make them in one spot (DHCP) rather than having to make the changes on each workstation. As far as performance there is probably no difference.

The choice for dynamic vs static also depends on the number of clients in your network. If you only have a few, then you can consider using static IP configuration.

BTW: It is possible to configure the DHCP server in FREESCO to give out the same IP address to a client based on the client's MAC address.
Using this feature can also be used to only allow “known” clients to your FREESCO router, although it is rather simple to 'fake' a MAC address.